The fracture of complete dentures fabricated using Polymethyl methacrylate resin constitutes a challenge to the clinician and remains an unresolved problem. To determine whether gradual increase in load or different posterior teeth positions in maxillary denture would influence the pattern of stress. Two groups of maxillary dentures were fabricated with different posterior teeth positions (Group I with teeth on the crest of the ridge; Group II with buccal to the crest of the ridge.) using casts prepared from prefabricated edentulous molds, with 5 dentures in each group. Two strain gauges were cemented on to the midline of each denture, one on the anterior palatal area and other on the posterior palatal area. The dentures were loaded from 0 to 110 N in steps of 10 N, and the strains induced were measured. Differences of the stress magnitudes between the 2 groups were statistically analyzed using Mann-Whitney U test. The anterior palatal area of the maxillary denture was dominated by a tensile stress, which was greater in the group II than in group I. The posterior palatal area was dominated by compressive stress but the outer placement of the maxillary teeth caused a significant decrease in the compressive stress. The high anterior tensile stress with compressive stress in the posterior palatal area during loading may be responsible for denture base fractures that initiate from the anterior palatal area. The buccal placement of posterior teeth may play a role in the fatigue fracture of the maxillary denture.

No abstract

No abstract

One of the most commonly faced problems among long term denture wearers is the reduction in the denture foundation. Prosthetic rehabilitation of a patient with severely resorbed ridge is the most challenging therapy a prosthodontist can undertake. In order to have a favourable prognosis for the denture therapy, impression technique selected should be based on the present state of the basal tissue support. This article presents the application of neutral zone concept being incorporated in impression making to achieve successful complete denture therapy.